Improvement in polarized armatures for electric bells



T. A. WATSON. v Polarized Armature for Electric Bells.

No. 2:0,886. PatentedDec. 17,1878

Inventor.-

UNITED STATES PATENT FFIGE.

THOMAS A. WATSON, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN POLARIZED ARMATURES FOR ELECTRIC BELLS.

Specification forming part of Letters Patent No. 210,886, dated December17, 1878; application filed August 1, 1878.

To all whom it may concern:

Be it known that I, THOMAS A. WATSON, of Boston, county of Suffolk, andState of Massachusetts, have invented a new and useful Improvement inElectric Bells, which improvement is fully set forth in the followingspecification.

My invention relates to, and is an improvement in, that class ofelectric bell strikers having their armatures and clectro-magnetspolarized by proximity to, or contact with, the poles of a permanentmagnet, and which are operated by alternately reversed currents ofelectricity.

The object of my invention is to secure greater simplicity ofconstruction and more powerful operation.

These ends I attain by havin the soft-iron armature pivoted in andparallel with a metal frame, (preferably malleable cast -iron,) to whichframe I also fasten the supports for the bells, the whole being securedfirmly to one pole of a permanent magnet, preferably of the horseshoeform. To the other pole of this magnet is fastened the clectro-magnet,with the cores parallel to each other and facing the armature. By thisarrangement the armature comes directly over the poles of theelect-romagnet and consequently is in the best position to be acted uponby the electric currents passing through the coils.

The armature has a hammer extending from the center of one side, whichplays between two hells when the armature is vibratin This will be seenclearly by reference to the accompanying drawing, in which- Figure 1represents a front, and Fig. 2 a side, elevation. of my improved bell,and Fig. 3, a modification in which a single bell is used.

A is one pole of the permanent magnet, and B the other. C is thearmature, pivoted at point (Z of the metal piece D, so that when one endisagainst the clectro-magnet the other is away from it.

E E are the supports for the bells F F. These are attached to the metalpiece 1) by screws passing through slotted holes, and the bells canthereby be adjusted in their relation to the hammer or striker G.

H H is an ordinary electro-magnet fastened to the pole B. Instead of thehorseshoe-magnet A B, one or more straight-bar magnets may be used,extending from the metal piece D to the back piece, J, of theelectro-magnet. A single bell may also be used, as in Fig. 3, byattaching a hammer or striker, G G, to each end of the armature G, andfastening the bellsupport to the metal piece D directly over the centerof the armature. The hammers can strike either on the inside or outsideof the bells.

When a current passes in one direction through the coils of theelcctro-magnet, the armature is attracted at one end and repelled at theother. WVhen a current passes in the opposite direction this action isreversed.

Having described my invention, What 1 claim,and desire to secure byLetters Patent, 1s-

1. The combination of the centrally-pivoted soft-iron armature, metalframe, and perma nent magnet or magnets, as and for the purpose setforth.

2. The combination of the electro-magnet, permanent magnet or magnets,and armature centrally pivoted and facing the ends of theelect-ro-magnet, as and for the purpose set forth.

In testimony whereof I have signed this specification in the presence oftwo subscrib ing witnesses.

THOMAS A. WVATSON.

Witnesses:

G. E. HUBBARD, Brennan W. FINN.

